#include <iostream>
using std::cout;
using std::endl;

// void swap(int a, int b){
//     int temp = a;
//     a = b;
//     b = temp;
// }

void swap(int *a, int *b){
    int temp = *a;
    *a = *b;
    *b = temp;
}

void swap(int &a, int &b ){
    int temp = a;
    a = b;
    b = temp;
}


void test0(){
    int swapA = 10;
    int swapB = 20;
    swap(swapA, swapB);
    swap(&swapA, &swapB);
}

int main(void){
    test0();
    return 0;
}

